A simple self-locking connector is provided to interconnect the adjacent ends of tubular conduits, particularly in aircraft, and for holding the conduits coupled to one another in a fluid-type relationship in the presence of vibrations. It is well known that connectors used on aircraft are subject to vibrations so that they may loosen and allow leakage. Consequently, there is a tendency for mechanics to tighten such connectors excessively and thereby damage them.
Many connectors have been proposed in the past in attempts to assure that their mating parts will be locked together and cannot be accidentally loosened as a result of vibrations. One approach has been to attach keepers to the connector which use lock wires, cotter pins, keys, back-up nuts, lock washers, etc. Although such keepers have proven to be effective for some purposes, they require extra parts and additional assembly operations. Also, it is particularly difficult to install the keepers when the connector is in a location which is not readily accessible.
Co-pending application Ser. No. 07/674,455, filed Mar. 225, 1991, in the name of the present inventor provides a self-locking connector which overcomes the disadvantages described above. The connector described in the co-pending application is simple and economical in its construction, and it is capable of being reused a large number of times. The connector disclosed in the application is also rugged in its construction and reliable in its operation. Specifically the connector described in the co-pending application comprises first and second tubular fittings which are held together in axially aligned sealed relationship by a nut which is coaxially positioned with respect to the two fittings. The nut is rotatbly mounted on the second fitting and its forward end is threaded into a threaded end of the first fitting.
The nut of the Co-pending Application has an internal flange at its rear end which engages an annular shoulder on the second fitting. As the nut is tighten onto the threaded end of the first fitting, it draws the two fittings together so that an annular sealing surface on the second fitting is drawn into sealing relationship with an annular seat in the end of the first fitting. An external integral hexagonal shoulder is formed coaxially on the first fitting of the connector of the co-pending application, and a frusto-conical Belleville type resilient washer is interposed between the hexagonal shoulder and the forward end of the nut. As the nut is tightened, its forward end engages the Belleville washer and compresses it axially as the sealing surface of the second fitting seats into the seat in the first fitting. The Belleville washer is compressed between the hexagonal shoulder and the end of the nut, and due to its sprig effect it creates a high frictional resistance to backward rotation of the nut. The adjacent edges of the Belleville washer and the nut are configured to define mating ramps, each ramp having an inclination angle which is greater than the helical angle of the threads of the nut and of the threaded end of the first fitting, so that the nut is effectively locked on the first fitting.
The connector of the present invention is similar in many respects to the connector of the co-pending application, and it incorporates all the favorable features of the connector of the co-pending application. However, the first fitting of the connector of the present invention has, for example, an L-shape, and does not include an integral hexagonal shoulder, as was the case of the first fitting of the co-pending application. Instead, a ramp is formed on the first fitting adjacent to the threaded end thereof, and the Belleville washer of the assembly of the co-pending application is replaced by a resilient slotted collar which engages the ramp on the first fitting in locking relationship, as will be described.